Dimensional versus nosographic approach to Alzheimer's disease: therapeutic implications

Negative results in therapeutic trials in Alzheimer's disease (AD) usually account for the nonefficacy of the presently tested drugs. However, methodological flaws in the design of these studies, related to the commonly used nosographic approach, can also be implicated in the lack of demonstration of beneficial results. With regard to the heterogeneity of clinical manifestations of AD, the interest of the dimensional, transnosographic approach to cognitive deficits and behavioral disturbances in dementia is suggested for these trials. Both approaches can also be combined, according to the presumed biochemical action of the tested drug in the preclinical studies and the aim of the trial.